Tag: 自带gzs安全吗

Shocking Irrigation Systems

first_imgThe condition of some farm irrigation systems is shocking.Literally.”We see an average of one death every year caused by electrical problems inirrigation systems,” said Kerry Harrison, an engineer with the University of GeorgiaExtension Service.”This is one thing farmers need to fix before it’s broken,” Harrison said.Most irrigation systems powered by three-phase electrical lines run on 480 volts. ButHarrison said it’s not the volts, but the amps that present the most danger.AMilliamps can kill a man,” he said. “But some of these larger systems have30 to 50 amps running through them.”As systems age, the parts wear. Conduits break, and insulators fray or crack and exposethe wires. They wear slowly, but they do wear. Eventually they threaten the farmer’ssafety.Bitter winter cold this year made conduits and wire insulation brittle and prone tocracking or breaking. If water entered the system, it could have frozen and expanded. Thiscould create more problems by causing shorts in the wiring.Harrison said farmers should inspect their irrigation electrical systems as a part oftheir routine maintenance. It’s best to inspect in early spring before the season’s firstuse.A thorough electrical system inspection includes checking for:* Broken insulation.* Exposed wiring.* Wiring run through an inappropriate conduit or not in a conduit.* Inadequate or no grounding.”Farmers can do their own inspection if they’re confident in their knowledge ofelectrical systems,” he said. “Or they can hire an electrician.”Before inspecting any electrical equipment, check for yourself that it’s turned off atthe main switch. Harrison also tests metal parts with a small pen-like indicator thatlights when electricity is present, just to be sure.If live exposed wires touch a metal part of the system, it becomes “hot,” or electrically charged. Ifsomeone touches the “hot” part, he can become the ground.Most electricians install a wire from the system’s metal frame to a metal rod pushedinto the soil. That provides a safe route for stray electricity to follow. This simplestep can prevent a person from becoming electrocuted.Other areas to inspect include disconnect switch boxes. “Some systems don’t even have disconnectswitches in the field. That’s dangerous. One needs to be installed immediately.”Many boxes aren’t as rodent-proof as they need to be, Harrison said. Birds, rats,squirrels or other small animals may have nested in the box over the winter. If notremoved, the nest could catch on fire from live wires, shorting out the system.Harrison said perils he sees often are wires strung across field surfaces. “I see that too much,”he said. These wires arevulnerable to damage from tractor or implement tires, animals and weather.Some farmers also burn off fields with exposed wires running through them, burning offprotective insulation. Without insulation, the “hot” wire can cause its own fire in dry grass or crop debris.Most accidents happen during everyday activities. “Farmers get so used to theequipment,” Harrison said, “they lose respect for it and the injury it cancause.” Farmers and others need to develop safe habits when working with their equipment,especially irrigation systems powered by generators.Safe habits include:* Touching electrically powered equipment with the back of your hand before graspingit.* Using a volt/ohmmeter to detect electricity where it’s not supposed to be.* Buying a light indicator to test metal equipment for an electrical charge (about$20).* Regular inspections for blackened areas around switches or outlets, arcing or exposedwires. These point to problems that need immediate repair.”One death a year from these problems is one too many,” Harrison said. “Farmers and operators needto be aware of the threat on their lives. Electricity doesn’t give you a second chance.”last_img read more

Wenger happy with patient Arsenal

first_img Press Association In the build-up to Podolski’s first goal just before half-time, City striker Nikica Jelavic went down under Mikel Arteta’s challenge inside the Arsenal half. It looked a foul on first viewing and while replays were less conclusive, Bruce was furious no free-kick was given. “The first goal, you have to say, it’s a typical Arsenal goal,” he said. “Sometimes you hold your hand up and say it’s a real quality goal. “But the big turning point in the game, we’re talking about a refereeing decision again. “I think everybody in the ground expected a free-kick to be given, we didn’t get it and again, a bit of quality from Arsenal – it’s a terrific finish from Podolski – and after playing really well we’re 2-0 down at half-time.” The Tigers had chances before that, with strikers Nikica Jelavic and Shane Long both threatening while Tottenham loanee Jake Livermore hit a post. Bruce said: “We had a real few chances, they really haven’t threatened our goal at all for 35 minutes, and then within seven minutes of half-time the game’s over. “(Long’s) was one where I don’t think he was expecting it to come to him, but we’ve had two or three. The keeper’s made a wonderful save from Jelavic, James Chester’s had a chance over the bar, Jake Livermore’s hit the post. “So we’ve had our opportunities and you hope you can take one. We haven’t and as I said, the first goal from Arsenal was a wonderful piece of football and then the second one, the whole game-changer for me, is that decision. “That’s wrong, that I’m talking about a referee’s decision.” Long was withdrawn at half-time and Bruce explained: “He’s got a whack to the back of his calf. He’ll be touch and go for the weekend, I would have thought.” Bruce also revealed forward Sone Aluko’s absence from the matchday squad was due to a hamstring injury. Hull started brightly at the KC Stadium but Aaron Ramsey gave Arsenal a 31st-minute lead and Lukas Podolski’s double secured a 3-0 win for Wenger’s men. That ensured they would hold on to fourth place in the Barclays Premier League ahead of Everton and Wenger said: “It was a big win. Arsene Wenger praised a patient performance from his Arsenal side as they saw off Hull to remain on course for Champions League qualification. “The first half was very physical, played at a very high pace, our defenders needed to be very strong on crosses in the air. “We looked dangerous when we went into their half and took advantage of that. “In the second half, when we scored the third goal we controlled the game completely.” Ramsey’s goal capped an impressive first league start since Boxing Day for the Welshman, while Wenger was also able to recall Mesut Ozil for his first appearance since March 11 following hamstring trouble. And the manager said: “We were having problems scoring goals away from home and (Ramsey) and Ozil give us a cutting edge in the final third that makes us much more dangerous. “Ozil has always the timing of the pass, the incisiveness of his passing helps you turn quickly from defence to attack. “Football is down to quality of the players and you could see that today.” Opposite number Steve Bruce was encouraged by his side’s performance but bemoaned missed opportunities and what he saw as a game-changing decision by referee Jon Moss. last_img read more

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